Aphids and Spider Mites

What are Aphids and Spider Mites?

Aphids and spider mites are common spring and summer pests. Generally referred to as ‘sap-sucking’ pests, these pests feed on plants by piercing a plant’s tissues to feed on the sap and cell contents within. You may find them on leaves, stems, bark, flowers, and even fruit. They’re not picky! Both multiply rapidly and can cause a lot of damage for such small creatures. Typical plant damage associated with aphids and mites includes wilted leaves or stems, dying branches and slowed or reduced growth. In Vermont, however, finding these pests in your yard is generally a sign that you are living in a healthy and functioning ecosystem. Unless a tree is already diseased, stressed, young, or otherwise struggling, these pests will not significantly harm a tree. 

Aphids

Aphids are small, soft bodied insects that can be found on a diverse range of home garden and landscape plants. They come in a variety of colors (some even look like little wooly fluffballs!) and can be found in large clusters, or colonies, usually on the underside of tender shoots and leaves. You may notice curling of leaves or new growth looking twisted as a result of an aphid infestation.

Because of all the sap these little pests consume, they excrete a sugary, sticky substance known as “honeydew.” This substance can attract other insects such as ants, wasps, bees, butterflies, and flies. Additionally, this honeydew substance can cause quite a mess on cars, decks, and other house surfaces. Sooty mold can grow on the honeydew, making it black and soot like in appearance. This sticky, black mess is usually the reason people don’t want aphids around. 

Spider Mites

Despite the name, spider mites aren’t spiders, but they are tiny members of the arachnid class. They can be difficult to spot to the naked eye. However, these little pests often create webs on their host plants. If an infestation is suspected, they can also be spotted by shaking a plant limb over a white piece of paper. They reproduce rapidly, love hot weather and are especially prevalent during the summer months. Spider mites like dry conditions and often target plants that are drought stressed. 

The first sign of spider mite damage is stippling of light dots on the leaves and can sometimes look bronze in color. As the mites continue to feed on the leaves, the leaves turn yellowish or reddish and drop off of the plant. As mentioned above, large amounts of webbing may cover leaves, twigs, and fruit of the plant. Damage is usually worse when compounded by water stress.

Management and Treatment Options

Most of the time, these pests do not need to be controlled or removed. If they are a nuisance to you or if infestation is causing too much harm to your plants, you have several options available for management. 

1. One of the best ways to manage an infestation of sap-sucking pests is to hose the infested plant down with water from your garden hose. 
2. Natural predators in your garden can help keep aphid and mite populations at a minimum. These natural predators include but are not limited to lady beetles, lacewings, parasitic wasps, and pirate bugs. Contact us to learn how we can help you improve your yard’s diversity and overall ecosystem health!
3. In some more severe situations, it may be necessary to apply chemical control. We recommend using low-toxicity products first if this is the case. Horticultural oils and insecticidal soaps are a good place to start. If you think this may be necessary, contact us! We can assess your plant and conduct treatments or make recommendations tailored to your plant and situation. 
4. Make sure your tree or plant is in good health otherwise. Ensure your plant is well watered and appropriately nourished to promote overall health and wellness. Pruning may be necessary in severe cases to remove dead or dying plant material. We can help!

If you suspect you have an aphid or spider mite infestation, or if you’d like more information about how to keep your plants safe from pests, contact us today! Our experts at Teacher’s Tree Service would be happy to help.

Citations/Resources

Barrett, Bruce A. 2008. “Aphids, Scales and Mites on Home Garden and Landscape Plants.” Extension.missouri.edu. Extension – University of Missouri. June 2008. https://extension.missouri.edu/publications/g7274.

Godfrey, L.D. 2011. “Spider Mites Management Guidelines–UC IPM.” Ipm.ucanr.edu. University of California Agriculture and Natural Resources. December 2011. https://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html.

Hahn, Jeffery, and Suzanne Wold-Burkness. 2020. “Twospotted Spider Mites in Home Gardens.” Extension.umn.edu. University of Minnesota. 2020. https://extension.umn.edu/yard-and-garden-insects/spider-mites.

Michigan State University Extension. n.d. “Spider Mites and Aphids.” Https://Www.canr.msu.edu/Lawn_garden/. Michigan State University. Accessed February 2, 2024. https://www.washtenaw.org/DocumentCenter/View/16622/Spider-Mites-and-Aphids.

UF/IFAS Extension. n.d. “Aphids, Mites, and Thrips – Gardening Solutions – University of Florida, Institute of Food and Agricultural Sciences.” Gardeningsolutions.ifas.ufl.edu. University of Florida. Accessed February 2, 2024. https://gardeningsolutions.ifas.ufl.edu/care/pests-and-diseases/pests/thrips.html.